feeding problems

My 9 week old son harry is very fussy with his feeds and often leaves an awful lot maybe 2-3oz at a time due to his being irritated and wriggly during a feed. He takes maybe the first oz easy but then I'm struggling with him being so wriggly and spitting it out. I wind him and then try again he may take a little but often he doesn't bother.

Any advice would be brilliant, I'm a first time mummy and feel like I'm failing my little boy.